Bobebt abbott haditeld



ROBERT ABBOTT HZAJJFIELD, OF WESTMINSTER, ENG-LAW.

MANUFACTURE OF ROLLS.

No Drawing.

To all whom it may concern:

'Be it known that I, Sir ROBERT ABBOTT 'HADFIELD, baronet, F. R. S., a subject of the v Considerable King of Great Britain and Ireland, residing at Westminster, England,.have invented Improvements in or Relating to the Manufacture of Metal Rolls, of which thefollowing is a specification.

diificulty has heretofore been experienced in producing rolls of -a durable character suitable for rolling metals or alloys, particularly metals or alloys of a hard nature. The present invention has reference to improvements in the manufacture of rolls of the kind referred to designed The carbon in the nickel chromium steel,

used may advantageously be of the order of about .6%, the nickel of the order of from about 2 up to say 315% and the chromium of the order of from about 2 to 3%. In the case where the rolls are made of chromium steel, or nickel steel, the chromium or nickel may vary up to 4 or 5%. The invention howeversis not limited to the particular percentages of the elements mentioned. Usually the steel will be free from or low in manganese. Satisfactory results have been obtained by forging down an alloy steel blank containing about 67% of carbon, about 2% of nickel and about 2% of chromium, to approximately the shape and dimensions of the required roll, then annealing the roll, as for instance by heating itvto from 700 to 80020., say to about 765 0., and allowing it to cool slowly, as for instance in the furnace in which the heating was eflected, then' machining the annealed roll to the desired finished shape. and heating the enlarged or working portion thereof uniformly to a hardening temperature of say about 87 5 to 880 (3., the journals or trunnions being heated to a less temperature, and then quenching the roll in oil. Thus treated, the said. enlarged portion of the roll had a hard- Speciflcation of Letters Patent.

hardening temperature.

ness corresponding to from about 93 to 98 as determined by the schleroscope. The ournals of the roll will usually be of aless degreeof hardness than the central or working portlon thereof. The degrees of hardness mentioned are only given by way of example. The hardness can be varied to suit the particular use to which the roll is to-be applied. The hardening temperature may in some cases be taken up to say 950 C.

In some cases it may be found advantageous to temper the hardness of the roll to a suitable extent. This can be done in any known or suitable way. For example, it

'can be done by heating the roll, after quenching it for a greater or less time in a suitable cooling medium, to a temperaturesay for example up to about 300 C. and then lmmersmg it in a suitable cooling me- Patented Oct. 14. 1919. Application filed June 24, 1919. Serial mIadaMs.

dium, for example oil at ordinary temperature, or it may be cooled in air.

Also, the hardened steel roll, whether tempered or not, may be heated uniformly to a temperature that may vary from 50 C.

to 200 C., by immersing it in a bath of oil up to 250 or 300 C., preferably from 100 heated to the desired temperature, allowing it to remain in the oil until it attains the temperature thereof, then withdrawing it from the oil, and allowing it to cool slowly in air or otherwise. In this way the toughness of the hardened, or hardened and tempered, steel roll can be increased in an advantageous manner without reducing or unduly reducing its hardness.

The heating of the roll to the desired hardening temperature may conveniently be effected in a gas burning furnace, the heat being directed mainly on to the central portion of the roll that is to be rendered hard and tough. Usually the roll will be heated while supported in a vertical position and its lower journal or lower and upper journals may be protected to some extent against overheating by placing it or them in or covering them with protecting means, during some portion of the heating process. The roll may" conveniently be rotated to insure uniform heating thereof and the heating be efiected slowly and, it may be, in stages, so asto gradually heat the roll to :the desired The surface of the roll may, if desired, be suitably protected against oxidation during the heating.

The quenching of the roll may also be done by suspending it .vertically and dipping it endwise into a bath of oil or other suitable quenching medium.

lVhen the roll is cast, instead of forged, approximately to shape, it may, especially in the case of high nickel steels, be annealed by heating it to a much higher temperature than that hereinbefore mentioned, say for example up to a temperature of about 1,200 or 1,300 0.

After the hardening process, or hardening and tempering or toughening roll can be suitably finished, as by grinding and polishing in known ways, to finally adapt it for any particular use.

Instead of forging or casting the roll initially, approximately to shape, it may be machined approximately to shape, from a suitable ingot or blank.

Instead of making-the whole roll of nickel chromium steel, or chromium steel, or nickelv steel, as described, it may be composed of an inner portion or core of iron or steel of a' different and, it may be, cheaper quality than nickel chromium steel or chromium steel, or nickel steel, and an outer tubular portion or covering of nickel chromium steel or chromium steel or nickel steel, heat treated as described to render it hard, tough and durable, the two portions being rigidly secured together in any convenient way, the

' outer portion being that portion actuallythree per cent., heating the working portion used in rolling. In either case the roll may be made hollow if desired.

Rolls constructed as described may be of plain cylindrical or other desired shape and are specially adapted to the cold rolling of metals and metallic alloys.

What I claim is 1. In the manufacture of a metal roll, forming the metal roll of nickel chromium steel in which the carbon present is of the order of about. six tenths per cent, the nickel of the order of from about two to three and one half per cent. and the chromium of the order of from about two to of said roll to a high temperature and harden ing it while at the desired hardening temperature by a suitable cooling medium, tempering the hardened portion of. the roll and afterward toughening the hardened and tempered portion of the roll by heating it to a temperature not exceeding about 300 C. and allowing it to cool.

2. A process for the manufacture of a roll of the kind herein referred to, said process Consisting in forming the roll approximately to shape'of nickel chromium steel, annealing said roll by heating it to a high temperature and allowing it to cool slowly, finishing said roll to shape, supporting it in a heating space and heating its enlarged working portion to a high temperature, hardening said portion of the roll while it is at the desired hardening temperature by immersing the processes, the

,50 C. to about 300 formly to a high temperature portion of the roll while it is at the desired hardening temperature by immersing the heated roll in oil, tempering said hardened working portion of the roll by heating it to a lower temperature than the hardening temperature and cooling it and toughening the hardened and tempered portion of the roll by heating it uniformly in oil at a temperature not exceeding about 300 C. and afterward allowing it to cool slowly.

4. A process for the manufacture of a metal roll, said process consisting in heating the enlarged working portion of a roll, formed of high quality steel, to a high temperature, hardening said portion of the roll by cooling it while at the desired hardening temperature by a cooling medium, tempering the hardened portion of the roll by heating it to a lower temperature than the hardening temperature and cooling it and toughening the hardened and tempered portion of the roll by heating it uniformly in oil to a term perature of from about 50 to 300 C. and allowing it to cool.

5. A process for the manufacture of a metal roll, said process consisting in heating the enlarged working portion of a roll formed of high quality alloy steel and of the required shape to a high temperature, in a heating space by the action thereon of flame while it is being rotated, hardening said portion of the roll while at the desired hardening temperature by quenching it in a cooling medium, tempering the hardened enlarged working portion of the 'roll by heating it to a suitable tempering temperature and cooling it and afterward toughening the hardened and tempered portion of the roll by heating the roll in a bath of oil uniformly to a temperature of from about C. and allowing it to cool slowly. I

6. A process for the manufacture of a roll of the kind herein referred to, said process consisting in forming said roll approximately to shape, and of nickel chromium steel of approximately the composition herein set forth, anneallng it, then forming it to the required finished shape, suspending it with its axis vertical in a heating space, heating its enlarged working portion uniby the direct applicationw thereto of heat while slowly rotating it, quenching the heated roll, at the about two to three decimal'five per cent. of

nickel, and about two to three per cent. of chromium annealing said roll, forming it 'high temperature, quenchin to the required finished shape, suspending it with its axis vertical in a heating space, heating its enlarged working portion to a it While at a hardening temperature of irom about 875 up to about 950 (1., by immersing it in a cooling liquid, tempering the hardened enlarged portion of the roll as set forth,and afterward toughening the hardened and tempered enlarged portion of the roll by immersing the roll in a bath of oil heated to a temperature of from about 100 to 200 C., removing it from said bath after it has been uniformly heated to this temperature and allowing it to cool slowly.

Signed at 22 Carlton House Terrace, London, En land, this fourth day of June, 1919.

3 R BERT ABBOTT HADFIELD. 

